The Zhivkov ouster brought rapid change in some political institutions, little or no change in others. The official name of the country dropped "people's" to become simply the Republic of Bulgaria. For two years, the BCP remained entrenched as the most powerful party, slowing reform and clinging tenaciously to economic and political positions gained under Zhivkov. But a new constitution was ratified in mid-1991, laying the basis for accelerated reform on all fronts.

The first few months of the Mladenov regime brought few of the dramatic changes seen in Czechoslovakia or the German Democratic Republic (East Germany) in the same period. Mladenov, who came to power without a personal following, left much of the old government in power and failed to separate state from party functions. Although initial reforms came from the Politburo, Mladenov achieved popularity by immediately legalizing political protest, giving the media unprecedented freedom, abolishing privileges of party officials, and scheduling free elections within six months. Article 1 of the 1971 constitution, which established the leading role of the BCP in Bulgarian government and society, was abolished in January 1990. Public repudiation of Zhivkov allowed his subordinates to treat him as a scapegoat, thus protecting themselves from blame by the proliferating opposition groups.

The Bulgarian communists avoided the immediate political rejection suffered by their East European comrades for several reasons. Because the BCP had begun as an indigenous Bulgarian movement in 1891, Bulgarians did not resent it as an artificially imposed foreign organization. In 1989 nearly one in nine Bulgarians belonged to the party, a very high ratio that included a large part of the intelligentsia. Early opposition groups were concentrated in Sofia and did not have the means to reach the more conservative hinterlands, reflecting a political dichotomy between town and country that had existed since pre-Ottoman times (see Electoral Procedures , this ch.). Visible reorganization and reform occurred in the BCP shortly after Zhivkov left power; the Politburo was abolished and some old-guard communists were purged. The BCP invited opposition representation in the government and conducted a series of round-table discussions with opposition leaders. In February 1990, Mladenov resigned as party chief, removing the stigma of party interference in government; in April, the State Council was abolished and Mladenov was named president.

The first free election of the postwar era, the national election of June 1990, was anticipated as an indicator of Bulgaria's post-Zhivkov political mood and as an end to the extreme uncertainty that followed the Zhivkov era. But the election results provided no decisive answers or conclusions. During the political maneuvering that preceded the election, the contest for control of the National Assembly narrowed to the BCP and the Union of Democratic Forces (UDF), a coalition of several major and many minor parties and groups with diverse interests (see The Union of Democratic Forces , this ch.). The BCP presented a reformist image, liberally blaming Zhivkov for national problems and changing its name to the Bulgarian Socialist Party (BSP) to stress that a new era had begun. In March an agreement with opposition groups had made approval of legislative proposals by the round table necessary before the BCP-dominated National Assembly could consider passage (see The Role of Unofficial Organizations , this ch.). The round table also signed accords defining future legal changes in the political system, including multiple parties, separation of powers, constitutional protection of media freedom, and legalization of private property.

The parliamentary election was followed by three months of inactivity and drift in the summer of 1990. Although the Council of Ministers had resigned immediately after the election, a new government was not formed until late August. BSP party official Andrei Lukanov finally became prime minister in an all-socialist cabinet because UDF and other opposition parties refused to form a coalition. At the same time, the National Assembly required several weeks to agree on compromise candidate Zheliu Zhelev to replace Mladenov as president. The most significant political situation was outside government institutions. The two major parties became deadlocked over UDF demands that the BSP acknowledge its responsibility for the economic ruin of Bulgaria, and that the government adopt the UDF plan for radical economic reform similar to that in Poland (see Market Reform , ch. 3). Although much of the Zhivkov old guard had been forced out in favor of middle-of-the road socialists in 1990, the UDF demands activated strong pockets of reaction. Zhelev, a dissident philosopher and UDF leader, spent the rest of 1990 seeking compromises among the factions.

The Lukanov government, tied to an aging, largely conservative constituency and full of little-known BSP figures, met few of the reform demands. In October Lukanov presented a 100-day economic reform plan to serve as a transition to longer-term planning in 1991. The plan borrowed major parts of the program advocated by the UDF. The National Assembly remained too divided on the reform issue to give Lukanov the legislative support he needed. Meanwhile, polls showed a definite drop in popular support for the BSP; under these circumstances, the UDF intensified efforts to turn out the government by refusing to support any of Lukanov's proposals.

In November Bulgaria was paralyzed by student demonstrations and general strikes called to topple Lukanov (see Trade Unions , this ch.). Lukanov's resignation ended the opposition's refusal to form a coalition government. Zhelev, who then commanded more political power than any other figure, proposed a compromise candidate, Dimitur Popov, as prime minister. Popov, a judge with no party allegiance, received a mandate to form a new cabinet and proceed with reforms as soon as possible. After considerable deliberation, cabinet posts were distributed among major factions, and reform legislation began slowly moving into the National Assembly in the first half of 1991.